1. Field of the Invention
The present invention relates to a communication apparatus for a vehicle operated by a passenger while wearing a helmet.
2. Background Art
When a passenger wears a helmet, the passenger's ability to hear sound occurring exterior of the helmet is severely hindered. Therefore, there has been proposed an apparatus in which a speaker is installed and a microphone is provided on the helmet, and communication is carried out between the helmet and the vehicular body by an infrared ray, thus, improving the passenger's ability to hear exterior sounds. (Japanese Unexamined Patent Publication No. 2-306732).
According to the patent publication, an acoustic apparatus is provided to the vehicle body side, a sound signal of the acoustic apparatus is converted into an infrared ray signal and transmitted to the helmet side. On the helmet side the infrared ray signal is converted into an electric signal and the speaker incorporated in the helmet is thereby driven to transmit sound to the passenger.
The infrared ray is utilized for the communication between the vehicle body and the helmet; therefore, a connection cord or the like is not necessary to facilitate sound transmission. This alleviates the inconvenience of having to operate the acoustic apparatus with a cord. Moreover, since the apparatus is wireless, connecting or disconnecting a cord when a passenger mounts or dismounts the vehicle is no longer required.
However, the acoustic apparatus of the patent publication has several disadvantages. First, as seen in the publication, the apparatus is applied to a motorcycle, where the acoustic apparatus is arranged between the handlebar and the seat of the motorcycle. Such an arrangement is inconvenient when a passenger is mounting and dismounting the motorcycle. In addition, such a placement of the apparatus increases the difficulty of operating the motorcycle.
Furthermore, since the transmitting/receiving unit of the acoustic apparatus is arranged on motorcycle handlebar (center), when the vehicle is operated with two passengers, the rear passenger is hindered from receiving sound communications transmitted by the transmitting/receiving unit. Therefore, in order to facilitate communications from the front passenger to the rear passenger, the acoustic apparatus of the patent publication employs significant operational members in order to accomplish the task of passenger to passenger communications. This unnecessarily increases manufacturing cost of the acoustic apparatus, and reduces the comfort level of the vehicle passengers. (refer to FIG. 8 in the publication).